Esbuild version 0.14.44 represents a minor update over its predecessor, version 0.14.43, within the rapidly evolving landscape of JavaScript and CSS bundlers. Both versions maintain the core promise of Esbuild: an extremely fast build process coupled with efficient minification. The primary distinction lies in the updated dependency versions of platform-specific binaries. Both dependencies and optionalDependencies sections reflect an upgrade from 0.14.43 to 0.14.44 for all supported architectures, including Linux (32-bit, 64-bit, ARM, ARM64, s390x, ppc64le, riscv64, mips64le), Windows (32-bit, 64-bit, ARM64), macOS (64-bit, ARM64), SunOS (64-bit), NetBSD (64-bit), Android (64-bit, ARM64), FreeBSD (64-bit, ARM64), and OpenBSD (64-bit).
For developers, this means upgrading to 0.14.44 ensures they are leveraging the latest bug fixes, performance improvements, and potentially new features implemented within the underlying platform-specific binaries. While the core API and functionalities remain consistent, this update guarantees optimal compatibility and performance across a wide array of operating systems and architectures. Furthermore, dependency updates often address security vulnerabilities, making it a worthwhile upgrade for maintaining a secure development pipeline. The release date difference also provides a sense of the update's freshness; version 0.14.44 was released approximately a week after 0.14.43, highlighting the active maintenance and incremental enhancements characteristic of the Esbuild project. While unpacked size grew marginally in the new release, the core promise of speed and efficiency are maintained.
All the vulnerabilities related to the version 0.14.44 of the package
esbuild enables any website to send any requests to the development server and read the response
esbuild allows any websites to send any request to the development server and read the response due to default CORS settings.
esbuild sets Access-Control-Allow-Origin: * header to all requests, including the SSE connection, which allows any websites to send any request to the development server and read the response.
https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L121 https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L363
Attack scenario:
http://malicious.example.com).fetch('http://127.0.0.1:8000/main.js') request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that's not the case for the reasons above.http://127.0.0.1:8000/main.js.In this scenario, I assumed that the attacker knows the URL of the bundle output file name. But the attacker can also get that information by
/index.html: normally you have a script tag here/assets: it's common to have a assets directory when you have JS files and CSS files in a different directory and the directory listing feature tells the attacker the list of files/esbuild SSE endpoint: the SSE endpoint sends the URL path of the changed files when the file is changed (new EventSource('/esbuild').addEventListener('change', e => console.log(e.type, e.data)))The scenario above fetches the compiled content, but if the victim has the source map option enabled, the attacker can also get the non-compiled content by fetching the source map file.
npm inpm run watchfetch('http://127.0.0.1:8000/app.js').then(r => r.text()).then(content => console.log(content)) in a different website's dev tools.Users using the serve feature may get the source code stolen by malicious websites.